150 gr. bullets should work just fine. I haven' t tried them in my Turk, but they shoot really well in my 98/22 and 98/29. I cannot remember what load I used for them though, I used 4064 for powder, others have told me that 3031 works even better for 150 gr bullets in the 8x57, but I haven' t had much time to experiment with 150 grainers in the last year.